Help with function

I need some help with writing a plpgsql function.  I want to return multiple items from the function.  How do I do this?

Here is my attempt at the function (note, this is a simple example that could obviously be done via a view, but I am trying to learn more about writing plpgsql functions):

create or replace function dba.active_transactions_by_db() returns setof integer pg_stat_activity.datname%TYPE as
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declare
    dbName            varchar;
    activeTransactions    integer;
    countRec        record;
begin
    for countRec in select count(1) as cnt, datname from pg_stat_activity group by datname loop
        return next countRec;
    end loop;
   
    return countRec;
end;
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language plpgsql;